As has hitherto been known, when an image is captured by means of an image processing apparatus such as a camera, deterioration sometimes arises in an image. Factors responsible for deterioration of an image include hand shake arising during image-capturing operation, various aberrations of an optical system, distortion of a lens, and the like.
In order to correct hand shake arising in an image-capturing operation, use of a lens actuation system and a circuit processing system has been known. For instance, a system which detects hand shake of a camera and compensates for the hand shake by means of actuating a predetermined lens in synchronism with the thus detected hand shake has hitherto been known as the lens actuation system (see the abstract of Japanese Patent Laid-Open Publication No. Hei 6-317824). Another known circuit processing system detects fluctuations in the optical axis of a camera by means of an angular velocity sensor, acquires from the detected angular velocity or the like a transmission function representing a blur acquired during the image-capturing operation, and subjects the captured image to inverse transformation of the acquired transmission function, to thus restore an image (see the abstract of Japanese Patent Laid-Open Publication No. Hei 11-24122).
Various images other than ordinary captured images, such as X-ray images, microscopic images, and the like, have been known to undergo deterioration or changes because of shake or other reasons.
A camera adopting the hand shake correction described in Japanese Patent Laid-Open Publication No. Hei 6-317824 requires a space for hardware which drives a lens, such as a motor or the like, and becomes bulky. Moreover, such hardware or a drive circuit for driving the hardware is also required, which in turn adds to cost. In the case of correction of hand shake described in Japanese Patent Laid-Open Publication No. Hei 11-24122, the above-described drawbacks are eliminated, but the following problems are presented. Namely, an image is theoretically restored by means of inverse conversion of the acquired transmission function. However, in reality, difficulty is encountered in restoring an image, for the following two reasons.
First, the acquired transmission function is highly susceptible to noise, a shake information error, and the like. By means of these nominal fluctuations, a value may show great variation. Therefore, a corrected image acquired through inverse conversion may be far different from an image captured without hand shake. Thus, the transmission function cannot be actually utilized. Second, when inverse conversion is performed in consideration of noise or the like, there can also be adopted a method for estimating a solution by means of singular value decomposition of a solution to simultaneous equations. However, the volume of calculation used for estimation becomes astronomically huge, and the risk of a failure to solve the equations is high.